marker-assisted selection in wheat - ictsd

310Marker-assisted selection – Current status and future perspectives in crops, livestock, forestry and fishSummaryFAO estimates that there are around 200 species in aquaculture. However, only a fewspecies have ongoing selective breeding programmes. Marker-assisted selection (MAS) isnot used in any aquaculture breeding scheme today. The aim of this chapter, therefore, isto review briefly the current status of aquaculture breeding schemes and to evaluate thepossibilities for MAS of aquaculture species. Genetic marker maps have been publishedfor some species in culture. The marker density of these maps is, in general, rather lowand the maps are composed of many amplified fragment length polymorphism (AFLP)markers anchored to few microsatellites. Some quantitative trait loci (QTL) have beenidentified for economically important traits, but they are not yet mapped at a high density.Computer simulations of within-family MAS schemes show a very high increase ingenetic gain compared with conventional family-based breeding schemes, mainly due tothe large family sizes that are typical for aquaculture breeding schemes. The use of geneticmarkers to identify individuals and their implications for breeding schemes with controlof inbreeding are discussed.